Molecular Physics | Thermodynamics Answers

How deep would you have to dive before the air in your middle ear would be

compressed to 75% of its initial volume? Assume for the beginning that the

temperature of the sea is constant as you dive. Take the atmospheric pressure at

height h = 0 is 0.1MPa, ρ is the density of water at 20 degrees Celsius 998.23 kg/ 𝑚3,

g = 9.81 𝑚𝑠-2

. A vessel having a capacity of 0.05 m3 contains a mixture of saturated water

2. A cylinder contains 1 kg of a certain fluid at an initial pressure of 20 bar.

The fluid is allowed to expand reversibly behind a piston according to a law pV2 = constant until

the volume is doubled. The fluid is then cooled reversibly at constant pressure until the piston

regains its original position ; heat is then supplied reversibly with the piston firmly locked in

position until the pressure rises to the original value of 20 bar. Calculate the net work done by the

fluid, for an initial volume of 0.05 m3

A diesel engine piston which has an area of 45 cm2 moves 5 cm during part

of suction stroke. 300 cm3 of fresh air is drawn in from the atmosphere. The pressure in the

cylinder during suction stroke is 0.9 × 105 N/m2 and the atmospheric pressure is 1.013 × 105 N/

m2. The difference between the suction and atmospheric pressure is accounted for flow resistance

in the suction pipe and inlet valve. Find the net work done during the process.

 2.5. A vessel of cylindrical shape is 50 cm in diameter and 75 cm high. It con￾tains 4 kg of a gas. The pressure measured with manometer indicates 620 mm of Hg above

atmosphere when barometer reads 760 mm of Hg. Determine :

(i) The absolute pressure of the gas in the vessel in bar.

(ii) Specific volume and density of the gas.

Oxygen (molar mass 32 kg/kmol) expands reversibly in a cylinder behind a piston at a constant pressure of 3.163 bar. The volume initially is 0.0112 m³ and finally is 0,0323 m³ , the initial temperature is 17.6 ⁰C. Calculate the heat supplied during the expansion in the correct unit to two decimal places. Assume oxygen to be a perfect gas and take the specific heat at constant pressure as = 0.917kJ / kg K and molar gas constant as = 8.314 J / kmol K.

If 20 g steam initially at 100 degree C is added to 60 g of ice initially at 0 degree C, then find the final

equilibrium temperature of the mixture.